Generally, when people complain about lack of skins for champs it's someone complaining about the following champs. Obviously there are random ones mixed in like Xerath but these seem to be the main three. Their pickrates are (source u.gg , combined all ranks all regions):
Taliyah - (doesn't even have a midlane pickrate but for jungle) is at 1%
Ornn - 3.6%
Rek'Sai - 2%
This means their combined pick rate is 6.6%. The classic champion people complain about getting skins is Kai'Sa. Her pickrate is 18.7%. Riot's skin team is not infinite. Their resources are limited. If Riot theoretically assigned a team to make a skin for each of those 3 champions, the combined sales of those three skins would be a third of if they made a Kai'sa skin. Essentially, 9 times as many resources would have to be used to match a single Kai'Sa skin.
However, the majority of players are in Silver and so the majority of skin sales would come from Silver players. In Silver:
Taliyah - I sh*t you not, Taliyah doesn't even exist in Silver. Her playrate is too small to be registered, both in mid and jngl
Ornn - 3.2%
Rek'Sai - 1.3%
This is a combined 4.6%, even lower than when combining all elos. Kai'Sa has a pickrate in Silver of 15.7%, so again about a third if they made a skin for each champion. It just isn't economical to put the resources and money into any one of those champs. I personally play alot of Rek'Sai and I like her base model more than any of the skins for her. Ornn has one of the best 1350 skins there is in Thunderlord (in my opinion) and Taliyah has just way too small of a pickrate for it to be economically the correct decision. I don't know why people make so many posts so angry about these champions not getting skins when for one chances are they wouldn't actually buy the skin themselves, and two when Riot at the end of the day has to make money.
Edit - shoutout to the guy who commented: "most people complaining about Hitler probably weren't Jews either, yet we don't blame them for hypocrisy."
Edit, some people are struggling so I'll clear some things up:
- "Riot might not make as much profit this year" - League is a free game. Riot has an insane amount of costs within the company on running Worlds, maintaining the game, paying staff etc. Their money does not go directly into profit, they rely on skins to keep the game afloat. Alot of people have literally no idea how business works. Stop commenting "it wouldn't hurt to make a Rek'Sai skin". This is the concept of opportunity cost. They have investments to make and costs to cover (seeing as they're releasing like 8 games this year), obviously, they will put resources into gaining 15 times more money when making skins, that's the nature of opportunity cost. If someone asked you to mow a lawn and said you can mow one of two identical lawns, exact same workload, but one would earn you £1 and the other £15, which lawn would you mow?
- Making skins take around 5-6 months, it's not something they can just do one afternoon. It's a resource commitment.
- "Those champs are overnerfed and unpopular while Kai'Sa is OP" - Lee Sin has a massive 28% playrate on patch 9.23. Lucian, who was pretty sh*t in 9.23 had a 18.7% playrate. When Taliyah was in her most broken state ever she never went above a 10% playrate, even in high elo. This argument is not relevant. These champs are just not enjoyed by much of the playerbase even when Taliyah was the most broken Jungler in the game